scholarly journals Implementation of the QUBE Force Field in SOMD for High-Throughput Alchemical Free Energy Calculations

Author(s):  
Lauren Nelson ◽  
Sofia Bariami ◽  
Chris Ringrose ◽  
Joshua Horton ◽  
Vadiraj Kurdekar ◽  
...  

<div><div><div><p>The quantum mechanical bespoke (QUBE) force field approach has been developed to facilitate the automated derivation of potential energy function parameters for modelling protein-ligand binding. To date the approach has been validated in the context of Monte Carlo simulations of protein-ligand complexes. We describe here the implementation of the QUBE force field in the alchemical free energy calculation molecular dynamics simulation package SOMD. The implementation is validated by demonstrating the reproducibility of absolute hydration free energies computed with the QUBE force field across the SOMD and GROMACS software packages. We further demonstrate, by way of a case study involving two series of non-nucleoside inhibitors of HIV-1 reverse transcriptase, that the availability of QUBE in a modern simulation package that makes efficient use of GPU acceleration will facilitate high-throughput alchemical free energy calculations.</p></div></div></div>

2020 ◽  
Author(s):  
Lauren Nelson ◽  
Sofia Bariami ◽  
Chris Ringrose ◽  
Joshua Horton ◽  
Vadiraj Kurdekar ◽  
...  

<div><div><div><p>The quantum mechanical bespoke (QUBE) force field approach has been developed to facilitate the automated derivation of potential energy function parameters for modelling protein-ligand binding. To date the approach has been validated in the context of Monte Carlo simulations of protein-ligand complexes. We describe here the implementation of the QUBE force field in the alchemical free energy calculation molecular dynamics simulation package SOMD. The implementation is validated by computing relative binding free energies for two congeneric series of non-nucleoside inhibitors of HIV-1 reverse transcriptase using QUBE and AMBER/GAFF force fields. The availability of QUBE in a modern simulation package that makes efficient use of GPU acceleration will greatly facilitate future high-throughput alchemical free energy calculation studies.</p></div></div></div>


2020 ◽  
Author(s):  
Lauren Nelson ◽  
Sofia Bariami ◽  
Chris Ringrose ◽  
Joshua Horton ◽  
Vadiraj Kurdekar ◽  
...  

<div><div><div><p>The quantum mechanical bespoke (QUBE) force field approach has been developed to facilitate the automated derivation of potential energy function parameters for modelling protein-ligand binding. To date the approach has been validated in the context of Monte Carlo simulations of protein-ligand complexes. We describe here the implementation of the QUBE force field in the alchemical free energy calculation molecular dynamics simulation package SOMD. The implementation is validated by computing relative binding free energies for two congeneric series of non-nucleoside inhibitors of HIV-1 reverse transcriptase using QUBE and AMBER/GAFF force fields. The availability of QUBE in a modern simulation package that makes efficient use of GPU acceleration will greatly facilitate future high-throughput alchemical free energy calculation studies.</p></div></div></div>


2021 ◽  
Author(s):  
Duvan Gonzalez ◽  
Luis Macaya ◽  
Esteban Vöhringer-Martinez

<div> <div> <div> <p>Host-guest systems are widely used in benchmarks as model systems to improve computational methods for absolute binding free energy predictions. Recent advances in sampling algorithms for alchemical free energy calculations and the increase in computational power have made their binding affinity prediction primarily dependent on the quality of the force field. Here, we propose a new methodology to derive the atomic charges of host-guest systems based on QM/MM calculations and the MBIS partitioning of the polarized electron density. A newly developed interface between the OpenMM and ORCA software package provides D-MBIS charges that best represent the guest’s average electrostatic interactions in the hosts or the solvent. The simulation workflow also calculates the average energy required to polarize the guest in the bound and unbound state. Alchemical free energy calculations using the GAFF force field parameters with D-MBIS charges improve the binding affinity prediction of six guests bound to two octa-acid hosts compared to the AM1-BCC charge set after correction with the average energetic polarization cost. This correction results from the difference in the energetic polarization cost between the bound and unbound state and contributes significantly to the binding affinity of anionic guests. </p></div></div></div><div><div><div> </div> </div> </div>


2021 ◽  
Author(s):  
Duvan Gonzalez ◽  
Luis Macaya ◽  
Esteban Vöhringer-Martinez

<div> <div> <div> <p>Host-guest systems are widely used in benchmarks as model systems to improve computational methods for absolute binding free energy predictions. Recent advances in sampling algorithms for alchemical free energy calculations and the increase in computational power have made their binding affinity prediction primarily dependent on the quality of the force field. Here, we propose a new methodology to derive the atomic charges of host-guest systems based on QM/MM calculations and the MBIS partitioning of the polarized electron density. A newly developed interface between the OpenMM and ORCA software package provides D-MBIS charges that best represent the guest’s average electrostatic interactions in the hosts or the solvent. The simulation workflow also calculates the average energy required to polarize the guest in the bound and unbound state. Alchemical free energy calculations using the GAFF force field parameters with D-MBIS charges improve the binding affinity prediction of six guests bound to two octa-acid hosts compared to the AM1-BCC charge set after correction with the average energetic polarization cost. This correction results from the difference in the energetic polarization cost between the bound and unbound state and contributes significantly to the binding affinity of anionic guests. </p></div></div></div><div><div><div> </div> </div> </div>


2019 ◽  
Author(s):  
Maximiliano Riquelme ◽  
Esteban Vöhringer-Martinez

In molecular modeling the description of the interactions between molecules forms the basis for a correct prediction of macroscopic observables. Here, we derive atomic charges from the implicitly polarized electron density of eleven molecules in the SAMPL6 challenge using the Hirshfeld-I and Minimal Basis Set Iterative Stockholder(MBIS) partitioning method. These atomic charges combined with other parameters in the GAFF force field and different water/octanol models were then used in alchemical free energy calculations to obtain hydration and solvation free energies, which after correction for the polarization cost, result in the blind prediction of the partition coefficient. From the tested partitioning methods and water models the S-MBIS atomic charges with the TIP3P water model presented the smallest deviation from the experiment. Conformational dependence of the free energies and the energetic cost associated with the polarization of the electron density are discussed.


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